<!doctype html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../navigation-methods/return-value/resources/helpers.js"></script>
<iframe id="i" src="/common/blank.html"></iframe>
<script>
promise_test(async t => {
  let start_length = navigation.entries().length;
  let start_index = navigation.currentEntry.index;

  // Wait for after the load event so that the navigation doesn't get converted
  // into a replace navigation.
  await new Promise(resolve => window.onload = () => t.step_timeout(resolve, 0));

  // Navigate the iframe, then the top window, so that when the iframe goes back
  // to its initial entry, the top window navigates as well.
  await i.contentWindow.navigation.navigate("#").finished;
  await navigation.navigate("#").finished;
  assert_equals(navigation.entries().length, start_length + 1);
  assert_equals(i.contentWindow.navigation.entries().length, 2);
  assert_equals(navigation.currentEntry.index, start_index + 1);
  assert_equals(i.contentWindow.navigation.currentEntry.index, 1);

  // Ensure the top window, which is allowed to cancel the traversal, does so.
  navigation.onnavigate = e => e.preventDefault();

  let top_navigateerror_fired = false;
  navigation.onnavigateerror = t.step_func(e => {
    assert_equals(e.constructor, ErrorEvent);
    assert_equals(e.filename, location.href);
    top_navigateerror_fired = true;
  });

  i.contentWindow.navigation.onnavigate = t.unreached_func("navigate event should not fire in the iframe, because the traversal was cancelled in the top window");
  i.contentWindow.navigation.onnavigateerror = t.unreached_func("navigateerror event should not fire in the iframe, because the navigate event was not fired");

  // When the top window blocks the traversal, it should be blocked in the
  // iframe as well, and the traversal promises in the iframe should be rejected.
  const iWindow = i.contentWindow;
  const iDOMException = iWindow.DOMException;
  await assertBothRejectDOM(t, i.contentWindow.navigation.traverseTo(i.contentWindow.navigation.entries()[0].key), "AbortError", iWindow, iDOMException);
  assert_true(top_navigateerror_fired);
  assert_equals(navigation.currentEntry.index, start_index + 1);
  assert_equals(i.contentWindow.navigation.currentEntry.index, 1);
}, "navigation.traverseTo() in an iframe with same-document preventDefault in its parent");
</script>
